Methods

Participants

  • We collected data from 180 participants 79 were tested in Oxford, and 101 were tested in Barcelona.
  • After applying trial- ad participant-level exclusion criteria, the sample comprise data from 94 (35 tested in Oxford, and 60 tested in Barcelona), and were included in our analyses.
  • 21 participants in the final sample were longitudinal (tested in at least one age group). 0 longitudinal participants were tested in Oxford and 21 were tested in Barcelona.
  • From the longitudinal participants, 0 were tested at two age groups, and 0were tested at three age groups.

Summary

Longitudinal

We collected data from 30 longitudinal participants, that is, who were tested in at least two of the three ages (21, 25, and 30). Of those, 0 were tested in Oxford, and 30 were tested in Barcelona.

Attrition (overall)

Attrition (by group)

This table shows a summary of the total, total valid, and proportion of valid monolingual and bilingual participants tested in each lab (Barcelona and Oxford), in each age group (21, 25, and 30 months), and the mean of valid trials they contributed in each trial type (cognate, non-cognate, and unrelated).

Age Group Laboratory Mean valid trials N participants
Cognate (8) Non-cognate (8) Unrelated (16) Valid Tested Valid (%)
21 months Bilingual Barcelona 1.76 1.68 2.29 20 41 48.78%
21 months Monolingual Barcelona 1.86 2.05 3.03 40 73 55.56%
21 months Monolingual Oxford 1.89 2.09 3.26 40 75 53.33%
25 months Bilingual Barcelona 2.28 1.89 3.50 14 20 70.00%
25 months Monolingual Barcelona 2.64 2.58 2.98 26 43 60.47%
25 months Monolingual Oxford 1.00 1.50 2.00 4 16 25.00%
30 months Bilingual Barcelona 2.15 2.26 2.63 22 35 62.86%
30 months Bilingual Oxford 2.00 1.25 2.75 2 4 50.00%
30 months Monolingual Barcelona 2.03 2.45 3.03 18 33 54.55%
30 months Monolingual Oxford 2.82 3.33 5.86 17 25 68.00%

Attrition (by participant)

Participant Location Lang. Profile Age Valid participant Valid trials (%) Invalid trials
Gaze (%) Vocabulary (%) Other (%)
100 Barcelona Bilingual 21 months TRUE 55.56% 11.11% 38.89% 33.33%
101 Barcelona Monolingual 21 months FALSE 0.00% 0.00% 100.00% 100.00%
102 Barcelona Monolingual 21 months TRUE 59.38% 25.00% 21.88% 15.62%
103 Barcelona Bilingual 21 months FALSE 25.00% 53.12% 40.62% 21.88%
104 Barcelona Monolingual 21 months FALSE 28.12% 50.00% 34.38% 21.88%
105 Barcelona Bilingual 21 months TRUE 51.72% 31.03% 20.69% 17.24%
106 Barcelona Bilingual 21 months FALSE 0.00% 100.00% 40.00% 0.00%
107 Barcelona Monolingual 21 months FALSE 34.38% 46.88% 28.12% 18.75%
108 Barcelona Bilingual 21 months TRUE 50.00% 43.75% 28.12% 6.25%
109 Barcelona Bilingual 21 months FALSE 31.25% 40.62% 53.12% 28.12%
111 Barcelona Bilingual 30 months TRUE 40.62% 12.50% 53.12% 46.88%
112 Barcelona Monolingual 21 months TRUE 40.62% 18.75% 50.00% 40.62%
113 Barcelona Monolingual 21 months TRUE 65.62% 12.50% 21.88% 21.88%
114 Barcelona Monolingual 21 months FALSE 34.38% 31.25% 37.50% 34.38%
115 Barcelona Monolingual 21 months TRUE 53.12% 43.75% 15.62% 3.12%
116 Barcelona Monolingual 21 months FALSE 34.38% 43.75% 40.62% 21.88%
117 Barcelona Bilingual 21 months FALSE 25.00% 53.12% 43.75% 21.88%
118 Barcelona Monolingual 21 months NA 0.00% 100.00% 100.00% 0.00%
119 Barcelona Monolingual 21 months TRUE 59.38% 12.50% 34.38% 28.12%
120 Barcelona Bilingual 21 months TRUE 40.62% 21.88% 50.00% 37.50%
121 Barcelona Monolingual 25 months FALSE 31.25% 37.50% 53.12% 31.25%
18 Barcelona Bilingual 30 months FALSE 0.00% 100.00% 18.75% 0.00%
19 Barcelona Bilingual 30 months TRUE 71.88% 12.50% 18.75% 15.62%
20 Barcelona Bilingual 30 months FALSE 15.62% 59.38% 43.75% 25.00%
21 Barcelona Bilingual 30 months TRUE 62.50% 15.62% 25.00% 21.88%
22 Barcelona Bilingual 30 months FALSE 31.25% 34.38% 53.12% 34.38%
23 Barcelona Monolingual 30 months FALSE 50.00% 18.75% 40.62% 31.25%
25 Barcelona Monolingual 30 months FALSE 3.12% 81.25% 40.62% 15.62%
26 Barcelona Bilingual 30 months TRUE 75.00% 6.25% 18.75% 18.75%
27 Barcelona Monolingual 30 months TRUE 71.88% 15.62% 18.75% 12.50%
28 Barcelona Monolingual 30 months FALSE 25.00% 53.12% 40.62% 21.88%
29 Barcelona Bilingual 30 months TRUE 46.88% 18.75% 43.75% 34.38%
30 Barcelona Monolingual 30 months FALSE 37.50% 37.50% 40.62% 25.00%
31 Barcelona Bilingual 30 months FALSE 25.00% 59.38% 43.75% 15.62%
32 Barcelona Bilingual 30 months TRUE 34.38% 34.38% 50.00% 31.25%
33 Barcelona Monolingual 30 months FALSE 34.38% 34.38% 43.75% 31.25%
34 Barcelona Bilingual 30 months TRUE 50.00% 18.75% 40.62% 31.25%
35 Barcelona Bilingual 30 months FALSE 0.00% 100.00% 51.72% 0.00%
36 Barcelona Monolingual 30 months TRUE 50.00% 6.25% 43.75% 43.75%
37 Barcelona Bilingual 25 months FALSE 43.75% 28.12% 40.62% 28.12%
38 Barcelona Monolingual 30 months FALSE 40.62% 12.50% 53.12% 46.88%
39 Barcelona Monolingual 30 months FALSE 40.62% 28.12% 43.75% 31.25%
40 Barcelona Monolingual 30 months TRUE 50.00% 21.88% 40.62% 28.12%
41 Barcelona Monolingual 30 months TRUE 43.75% 21.88% 43.75% 34.38%
42 Barcelona Bilingual 30 months FALSE 37.50% 40.62% 40.62% 21.88%
43 Barcelona Bilingual 30 months TRUE 34.38% 28.12% 43.75% 37.50%
44 Barcelona Bilingual 30 months FALSE 0.00% 100.00% 50.00% 0.00%
45 Barcelona Bilingual 21 months TRUE 40.62% 43.75% 40.62% 15.62%
47 Barcelona Monolingual 21 months FALSE 15.62% 78.12% 28.12% 6.25%
48 Barcelona Bilingual 21 months FALSE 28.12% 56.25% 43.75% 15.62%
49 Barcelona Monolingual 21 months TRUE 40.62% 9.38% 53.12% 50.00%
49 Barcelona Monolingual 25 months TRUE 65.62% 18.75% 18.75% 15.62%
50 Barcelona Monolingual 21 months TRUE 59.38% 18.75% 31.25% 21.88%
50 Barcelona Monolingual 25 months TRUE 71.88% 9.38% 21.88% 18.75%
51 Barcelona Monolingual 21 months FALSE 25.00% 60.71% 28.57% 14.29%
51 Barcelona Monolingual 25 months TRUE 46.88% 46.88% 15.62% 6.25%
52 Barcelona Monolingual 21 months TRUE 37.50% 31.25% 43.75% 31.25%
52 Barcelona Monolingual 25 months FALSE 18.75% 59.38% 50.00% 21.88%
53 Barcelona Monolingual 25 months FALSE 37.50% 28.12% 50.00% 34.38%
53 Barcelona Monolingual 30 months TRUE 59.38% 15.62% 28.12% 25.00%
54 Barcelona Monolingual 21 months TRUE 68.75% 6.25% 25.00% 25.00%
54 Barcelona Monolingual 25 months TRUE 56.25% 9.38% 43.75% 34.38%
55 Barcelona Bilingual 21 months TRUE 50.00% 18.75% 40.62% 31.25%
55 Barcelona Bilingual 25 months TRUE 43.75% 21.88% 40.62% 34.38%
56 Barcelona Monolingual 21 months FALSE 53.12% 31.25% 21.88% 15.62%
57 Barcelona Bilingual 21 months FALSE 28.12% 40.62% 53.12% 31.25%
57 Barcelona Bilingual 25 months FALSE 31.25% 46.88% 53.12% 21.88%
58 Barcelona Bilingual 30 months TRUE 40.62% 15.62% 53.12% 43.75%
58 Barcelona Monolingual 25 months TRUE 50.00% 25.00% 31.25% 25.00%
59 Barcelona Monolingual 25 months TRUE 78.12% 6.25% 15.62% 15.62%
59 Barcelona Monolingual 30 months TRUE 65.62% 21.88% 15.62% 12.50%
60 Barcelona Bilingual 25 months TRUE 75.00% 9.38% 21.88% 15.62%
60 Barcelona Bilingual 30 months TRUE 81.25% 12.50% 6.25% 6.25%
61 Barcelona Bilingual 25 months TRUE 40.62% 18.75% 43.75% 40.62%
62 Barcelona Monolingual 21 months FALSE 31.25% 37.50% 40.62% 31.25%
64 Barcelona Monolingual 25 months FALSE 28.12% 68.75% 6.25% 3.12%
64 Barcelona Monolingual 30 months TRUE 53.12% 12.50% 43.75% 34.38%
65 Barcelona Monolingual 25 months FALSE 28.12% 68.75% 25.00% 3.12%
65 Barcelona Monolingual 30 months TRUE 46.88% 25.00% 40.62% 28.12%
66 Barcelona Bilingual 25 months TRUE 56.25% 18.75% 28.12% 25.00%
67 Barcelona Bilingual 25 months TRUE 31.25% 50.00% 40.62% 18.75%
67 Barcelona Bilingual 30 months FALSE 18.75% 62.50% 40.62% 18.75%
68 Barcelona Bilingual 25 months TRUE 50.00% 37.50% 18.75% 12.50%
69 Barcelona Monolingual 25 months TRUE 50.00% 28.12% 31.25% 21.88%
69 Barcelona Monolingual 30 months TRUE 56.25% 28.12% 21.88% 15.62%
70 Barcelona Monolingual 21 months FALSE 40.62% 46.88% 25.00% 12.50%
70 Barcelona Monolingual 25 months FALSE 28.12% 71.88% 0.00% 0.00%
71 Barcelona Bilingual 21 months TRUE 50.00% 31.25% 31.25% 18.75%
72 Barcelona Monolingual 21 months TRUE 68.75% 18.75% 12.50% 12.50%
72 Barcelona Monolingual 25 months TRUE 46.88% 15.62% 40.62% 37.50%
73 Barcelona Monolingual 21 months TRUE 37.50% 40.62% 43.75% 21.88%
73 Barcelona Monolingual 25 months FALSE 3.12% 87.50% 43.75% 9.38%
74 Barcelona Monolingual 25 months TRUE 68.75% 25.00% 15.62% 6.25%
74 Barcelona Monolingual 30 months FALSE 3.12% 96.88% 15.62% 0.00%
75 Barcelona Monolingual 25 months TRUE 53.12% 31.25% 28.12% 15.62%
76 Barcelona Bilingual 21 months FALSE 15.62% 68.75% 31.25% 15.62%
76 Barcelona Bilingual 25 months TRUE 50.00% 40.62% 25.00% 9.38%
77 Barcelona Monolingual 21 months TRUE 37.50% 15.62% 50.00% 46.88%
78 Barcelona Monolingual 21 months FALSE 0.00% 100.00% 100.00% 0.00%
78 Barcelona Monolingual 25 months TRUE 53.12% 18.75% 34.38% 28.12%
79 Barcelona Monolingual 21 months FALSE 31.25% 46.88% 40.62% 21.88%
80 Barcelona Bilingual 21 months FALSE 28.12% 46.88% 40.62% 25.00%
80 Barcelona Bilingual 30 months TRUE 62.50% 18.75% 18.75% 18.75%
81 Barcelona Monolingual 21 months TRUE 37.50% 40.62% 50.00% 21.88%
81 Barcelona Monolingual 25 months TRUE 43.75% 34.38% 31.25% 21.88%
82 Barcelona Monolingual 21 months TRUE 46.88% 18.75% 40.62% 34.38%
82 Barcelona Monolingual 25 months FALSE 37.50% 31.25% 40.62% 31.25%
83 Barcelona Monolingual 21 months FALSE 18.75% 59.38% 43.75% 21.88%
84 Barcelona Monolingual 21 months TRUE 43.75% 25.00% 40.62% 31.25%
84 Barcelona Monolingual 25 months FALSE 31.58% 31.58% 42.11% 36.84%
85 Barcelona Monolingual 21 months FALSE 16.67% 66.67% 46.67% 16.67%
86 Barcelona Bilingual 21 months TRUE 31.25% 28.12% 53.12% 40.62%
86 Barcelona Bilingual 25 months FALSE 37.50% 31.25% 40.62% 31.25%
87 Barcelona Monolingual 21 months FALSE 37.50% 34.38% 50.00% 28.12%
88 Barcelona Bilingual 21 months FALSE 21.88% 56.25% 40.62% 21.88%
89 Barcelona Monolingual 21 months TRUE 62.50% 21.88% 18.75% 15.62%
90 Barcelona Bilingual 21 months TRUE 62.50% 15.62% 28.12% 21.88%
91 Barcelona Monolingual 21 months FALSE 40.62% 43.75% 31.25% 15.62%
92 Barcelona Monolingual 21 months TRUE 37.50% 25.00% 50.00% 37.50%
92 Barcelona Monolingual 25 months TRUE 37.50% 53.12% 31.25% 9.38%
93 Barcelona Bilingual 21 months TRUE 37.50% 25.00% 43.75% 37.50%
94 Barcelona Monolingual 21 months TRUE 59.38% 25.00% 15.62% 15.62%
95 Barcelona Monolingual 21 months FALSE 25.00% 53.12% 37.50% 21.88%
96 Barcelona Monolingual 21 months TRUE 40.62% 37.50% 34.38% 21.88%
97 Barcelona Monolingual 21 months TRUE 40.62% 43.75% 34.38% 15.62%
98 Barcelona Bilingual 21 months FALSE 47.83% 21.74% 39.13% 30.43%
99 Barcelona Bilingual 21 months FALSE 30.77% 53.85% 23.08% 15.38%
210059 Oxford Monolingual 21 months TRUE 62.50% 15.62% 25.00% 21.88%
210060 Oxford Monolingual 21 months FALSE 18.75% 59.38% 46.88% 21.88%
210061 Oxford Monolingual 21 months TRUE 56.25% 25.00% 34.38% 18.75%
210062 Oxford Monolingual 21 months TRUE 46.88% 15.62% 43.75% 37.50%
210063 Oxford Monolingual 21 months TRUE 46.88% 43.75% 25.00% 9.38%
210064 Oxford Monolingual 21 months FALSE 25.00% 62.50% 31.25% 12.50%
210065 Oxford Monolingual 21 months TRUE 59.38% 31.25% 18.75% 9.38%
210067 Oxford Monolingual 21 months TRUE 43.75% 31.25% 34.38% 25.00%
210068 Oxford Monolingual 21 months FALSE 25.00% 59.38% 31.25% 15.62%
210069 Oxford Monolingual 21 months FALSE 37.50% 34.38% 37.50% 28.12%
210070 Oxford Monolingual 21 months FALSE 0.00% 6.25% 100.00% 93.75%
210071 Oxford Monolingual 21 months TRUE 53.12% 21.88% 34.38% 25.00%
210072 Oxford Monolingual 21 months FALSE 28.12% 15.62% 71.88% 56.25%
210073 Oxford Monolingual 21 months TRUE 59.38% 6.25% 37.50% 34.38%
210074 Oxford Monolingual 21 months FALSE 0.00% 21.88% 100.00% 78.12%
210075 Oxford Monolingual 21 months FALSE 25.00% 65.62% 31.25% 9.38%
210076 Oxford Monolingual 21 months TRUE 81.25% 9.38% 12.50% 9.38%
210077 Oxford Monolingual 21 months TRUE 81.25% 9.38% 15.62% 9.38%
210078 Oxford Monolingual 21 months FALSE 18.75% 62.50% 46.88% 18.75%
210079 Oxford Monolingual 21 months TRUE 59.38% 25.00% 25.00% 15.62%
210080 Oxford Monolingual 21 months FALSE 31.25% 62.50% 12.50% 6.25%
210081 Oxford Monolingual 21 months TRUE 53.12% 37.50% 12.50% 9.38%
210082 Oxford Monolingual 21 months FALSE 0.00% 28.12% 100.00% 71.88%
210083 Oxford Monolingual 21 months FALSE 26.67% 40.00% 40.00% 33.33%
210084 Oxford Monolingual 21 months FALSE 18.75% 37.50% 62.50% 43.75%
210085 Oxford Monolingual 21 months TRUE 68.75% 12.50% 28.12% 18.75%
210086 Oxford Monolingual 21 months TRUE 50.00% 31.25% 21.88% 18.75%
210087 Oxford Monolingual 21 months TRUE 53.12% 9.38% 40.62% 37.50%
210088 Oxford Monolingual 21 months TRUE 56.25% 12.50% 37.50% 31.25%
210089 Oxford Monolingual 21 months TRUE 43.75% 21.88% 37.50% 34.38%
210090 Oxford Monolingual 21 months FALSE 59.38% 28.12% 15.62% 12.50%
210092 Oxford Monolingual 21 months FALSE 31.25% 68.75% 3.12% 0.00%
210093 Oxford Monolingual 21 months TRUE 75.00% 21.88% 6.25% 3.12%
210094 Oxford Monolingual 21 months TRUE 81.25% 6.25% 15.62% 12.50%
210095 Oxford Monolingual 21 months FALSE 31.25% 34.38% 53.12% 34.38%
210096 Oxford Monolingual 21 months TRUE 75.00% 9.38% 15.62% 15.62%
210098 Oxford Monolingual 21 months FALSE 0.00% 12.50% 100.00% 87.50%
210099 Oxford Monolingual 21 months FALSE 6.25% 78.12% 71.88% 15.62%
24101 Oxford Monolingual 25 months FALSE 0.00% 28.12% 100.00% 71.88%
24713 Oxford Monolingual 25 months FALSE 0.00% 70.00% 100.00% 30.00%
24714 Oxford Monolingual 25 months FALSE 0.00% 46.88% 100.00% 53.12%
24715 Oxford Monolingual 25 months FALSE 0.00% 50.00% 100.00% 50.00%
25001 Oxford Monolingual 25 months TRUE 90.62% 6.25% 3.12% 3.12%
25002 Oxford Monolingual 25 months TRUE 78.12% 15.62% 6.25% 6.25%
25003 Oxford Monolingual 25 months FALSE 31.25% 28.12% 53.12% 40.62%
25004 Oxford Monolingual 25 months FALSE 0.00% 28.12% 100.00% 71.88%
270032 Oxford Bilingual 30 months FALSE 0.00% 60.00% 100.00% 40.00%
270034 Oxford Monolingual 30 months TRUE 78.12% 9.38% 12.50% 12.50%
270035 Oxford Monolingual 30 months FALSE 0.00% 12.50% 100.00% 87.50%
270036 Oxford Bilingual 30 months TRUE 68.75% 15.62% 18.75% 15.62%
30432 Oxford Monolingual 30 months FALSE 0.00% 18.75% 100.00% 81.25%
30434 Oxford Monolingual 30 months TRUE 68.75% 18.75% 12.50% 12.50%
30435 Oxford Monolingual 30 months FALSE 0.00% 28.12% 100.00% 71.88%
30436 Oxford Monolingual 30 months TRUE 90.62% 9.38% 0.00% 0.00%
30437 Oxford Monolingual 30 months TRUE 65.62% 34.38% 0.00% 0.00%
30438 Oxford Monolingual 30 months TRUE 81.25% 3.12% 15.62% 15.62%
30439 Oxford Monolingual 30 months TRUE 34.38% 59.38% 12.50% 6.25%
30440 Oxford Monolingual 30 months FALSE 53.12% 37.50% 18.75% 9.38%
30441 Oxford Monolingual 30 months TRUE 46.88% 50.00% 6.25% 3.12%
30442 Oxford Monolingual 30 months TRUE 68.75% 31.25% 0.00% 0.00%
30443 Oxford Monolingual 30 months TRUE 46.88% 50.00% 6.25% 3.12%
30444 Oxford Monolingual 30 months TRUE 96.88% 3.12% 0.00% 0.00%
30445 Oxford Monolingual 30 months TRUE 84.38% 15.62% 3.12% 0.00%

Attrition (by trials)

Trial type 21 months 25 months 30 months
Not valid Valid Not valid Valid Not valid Valid
Barcelona - Bilingual
Cognate 111 83 65 63 93 89
Non-cognate 115 76 72 56 95 89
Unrelated 269 111 142 114 247 120
Barcelona - Monolingual
Cognate 223 167 165 171 95 89
Non-cognate 198 192 159 181 86 98
Unrelated 480 301 426 248 230 138
NA 32 0 0 0 0 0
Oxford - Bilingual
Cognate 0 0 0 0 8 6
Non-cognate 0 0 0 0 9 5
Unrelated 0 0 0 0 18 11
Oxford - Monolingual
Cognate 174 125 39 14 58 62
Non-cognate 162 138 34 18 50 70
Unrelated 359 241 79 32 111 129

Materials

Procedure

Data analysis

Vocabulary data

We collected vocabulary data from participants. In Oxford, participants were sent the online version of the Oxford Communicative Development Inventory [OCDI; @hamilton2000] two weeks before each appointment. In Barcelona, participants were sent the online vocabulary inventory MultiLex immediately after the appointment, and were given two weeks to fill it. In Oxford, families filled the vocabulary checklist in the testing language, and when the participant was monolingual, also in the second language. In Barcelona, all participants filled the Catalan and the Spanish versions of the vocabulary checklists. All checklists included the words involved in the trial lists. When filling the vocabulary checklist, families checked each word as being understood, understood and produced or none. Each response to either checklist was aggregated to produce several vocabulary measures:

  • Total vocabulary: total number of words the child knows, summing up both languages. For instance, a child who knows 210 words in Catalan and 100 words in Spanish would have a total vocabulary size of 210 words.
  • L1 vocabulary: number of words the child knows in the languages of higher exposure (i.e., testing language). For instance, for a child exposed to 75% Catalan who knows 210 words in Catalan and 100 words in Spanish, their L1 vocabulary size would be 210 words.
  • Conceptual vocabulary: number of lexicalised concepts, that is, the number of concepts for which the child knows a word in at least one of the languages. For example, a Catalan-Spanish bilingual that knows taula and mesa – Catalan and Spanish translations of table– would have a conceptual vocabulary size of 1.

Vocabulary sizes of participants whose families failed to complete the vocabulary checklists were imputed, by assigning them the most likely vocabulary size from a distribution of vocabulary sizes of children of similar age (\(\pm\) 1 month) and language profile (similar exposure to a second language, \(\pm\) 10%) that completed the same vocabulary checklist previously.

Gaze data

Each trial was divided into 100 ms time bins. for each time bin, the proportion of target fixations were calculated, from the total of fixations to the target, distractor and the rest of the screen for that same time bin. Proportions were then aggregated across trials for each time bin and participants, so that each participant contributed with 20 data points (one for each time bin) for each trial type (cognate, non-cognate, and unrelated).

Workflow

Trial-level inclusion criteria

  • \(\geq\) 50% or more valid samples during prime phase (1,500 ms)
  • \(\geq\) 50% or more valid samples during target-distractor phase (2,000 ms)
  • At least one sample in target and one sample in distractor
  • Participant understands prime word in both languages
  • Participant knows the target word in the test language
  • Participant knows the distractor word in the test language

Participant-level inclusion criteria

  • \(\geq\) 4 trials in Cognate condition (50%, from a total of 8)
  • \(\geq\) 4 trials in Non-cognate condition (50%, from a total of 8)
  • \(\geq\) 8 trials in Unrelated condition (50%, from a total of 16)
  • \(\geq\) 36 gestational weeks
  • \(\geq\) 2,800g birth weight
  • No diagnosed developmental, hearing, or visual disorders
  • Not exposed to more than 10% to a 3rd language

Results

Target fixations

Aggregated by trial

For each participant and trial, the proportion of fixations to the target object were calculated from the total of fixations to the target, the distractor, and the rest of the screen. Then proportions for the same participant were aggregated within conditions, so that for each participant three data points were obtained: one in each trial type (cognate, non-cognate, and unrelated). Some participants were longitudinal. Scores form longitudinal participant are indicated by grey lines linking data points from the same participant.

Growth curve analysis

Model details

We fit a multilevel regression model using the lmer function of the lme4 package, used the following formula:

elog ~ age_group + trial_type * lp * (ot1 + ot2 + ot3) +
(1 + ot1 + ot2 + ot3 + trial_type + age_group | participant)

The formal implementation of this model is:

\[ \log(\frac{p}{n - q}) = (\beta_{0} + \beta_{0p} + \beta_{0i}) + ... \\ (\beta_{1} + \beta_{1p} + \beta_{1i})\times Condition_{pi} + ... \\ (\beta_{2} + \beta_{2i}) \times Group_{pi} + ... \\ (\beta_{3} + \beta_{3i}) \times (Condition_{pi} \times Group_{pi}) + ... \\ (\beta_{4} + \beta_{4p}) \times Vocabulary_{p} + \varepsilon_{pi} \]

Fixed effects

NULL

Predictor Estimate SE CI95% t df p
(Intercept) 0.17 0.05 [0.06, 0.27] 3.04 51.70 0.004
age_group.L 0.06 0.07 [−0.08, 0.20] 0.89 53.14 0.377
age_group.Q −0.12 0.08 [−0.28, 0.04] −1.42 27.50 0.166
vocab_size 0.20 0.17 [−0.13, 0.54] 1.19 90.55 0.238
trial_type1 0.01 0.06 [−0.10, 0.13] 0.25 88.51 0.803
trial_type2 −0.08 0.13 [−0.34, 0.18] −0.60 90.41 0.550
lp1 −0.03 0.10 [−0.23, 0.16] −0.34 75.53 0.734
ot1 0.48 0.21 [0.08, 0.89] 2.33 97.98 0.022
ot2 −1.43 0.14 [−1.70, −1.17] −10.47 99.29 0.000
ot3 0.89 0.12 [0.66, 1.12] 7.45 108.18 0.000
trial_type1:lp1 0.11 0.12 [−0.12, 0.34] 0.94 74.85 0.350
trial_type2:lp1 −0.11 0.27 [−0.63, 0.41] −0.43 81.17 0.669
trial_type1:ot1 0.01 0.11 [−0.20, 0.22] 0.10 34,147.21 0.919
trial_type2:ot1 0.06 0.22 [−0.36, 0.49] 0.30 34,181.52 0.763
trial_type1:ot2 0.17 0.11 [−0.04, 0.38] 1.61 34,009.05 0.107
trial_type2:ot2 −0.13 0.22 [−0.55, 0.30] −0.58 34,189.01 0.560
trial_type1:ot3 −0.06 0.11 [−0.27, 0.15] −0.59 33,833.53 0.556
trial_type2:ot3 −0.34 0.21 [−0.76, 0.09] −1.56 34,080.60 0.118
lp1:ot1 0.19 0.41 [−0.62, 1.00] 0.46 96.01 0.647
lp1:ot2 0.33 0.27 [−0.19, 0.86] 1.24 87.48 0.217
lp1:ot3 −0.30 0.24 [−0.77, 0.17] −1.25 108.79 0.215
trial_type1:lp1:ot1 −0.17 0.21 [−0.59, 0.26] −0.77 34,146.97 0.440
trial_type2:lp1:ot1 −0.37 0.43 [−1.21, 0.47] −0.86 34,182.01 0.390
trial_type1:lp1:ot2 −0.41 0.21 [−0.83, 0.01] −1.90 34,012.76 0.058
trial_type2:lp1:ot2 0.92 0.43 [0.08, 1.76] 2.14 34,188.63 0.033
trial_type1:lp1:ot3 0.12 0.21 [−0.30, 0.54] 0.57 33,828.87 0.571
trial_type2:lp1:ot3 0.34 0.43 [−0.50, 1.18] 0.78 34,080.63 0.433

Random effects

Marginal means

Overall

By vocabulary size

By location

21 month-old monolinguals

NULL

Predictor Estimate SE CI95% t df p
(Intercept) −0.05 0.06 [−0.18, 0.07] −0.82 31.45 0.421
vocab_size 0.22 0.25 [−0.26, 0.70] 0.89 32.46 0.379
trial_type1 0.12 0.08 [−0.04, 0.27] 1.46 31.33 0.155
trial_type2 0.19 0.14 [−0.09, 0.47] 1.30 30.57 0.202
ot1 1.08 0.22 [0.64, 1.51] 4.81 32.70 0.000
ot2 −1.11 0.20 [−1.50, −0.72] −5.55 34.71 0.000
ot3 0.44 0.17 [0.12, 0.77] 2.67 40.45 0.011
trial_type1:ot1 −0.69 0.16 [−1.01, −0.38] −4.34 9,556.24 0.000
trial_type2:ot1 −0.72 0.32 [−1.36, −0.09] −2.23 9,683.81 0.026
trial_type1:ot2 −0.18 0.16 [−0.49, 0.14] −1.10 9,483.87 0.271
trial_type2:ot2 0.26 0.32 [−0.37, 0.89] 0.80 9,695.34 0.422
trial_type1:ot3 0.38 0.16 [0.07, 0.69] 2.37 9,492.49 0.018
trial_type2:ot3 0.00 0.32 [−0.63, 0.63] 0.01 9,659.47 0.996

Vocabulary

This figure represents the vocabulary size in the dominant language of participants in the Y-axis and their linguistic profile in the X-axis. Results are presented separately for each age group. The shape of the violins, represents the distribution of the vocabulary sizes. The box-plot inside each violin represents the median, 25th and 75th percentiles, and the vertical lines represent the minimum and maximum values. vocabulary sizes in the dominant language were calculated as the proportion of items each participant was reported to understand or understand and say in the language of most exposure. for example, for a participant exposed mostly to Catalan, their vocabulary size in the dominant language was calculated as the proportion of words they were reported to understand and/or say in Catalan, from a total of ~200 words.

Appendix

References